This is the reception area at Lego world headquarters in Billund, Denmark. CNET reporter Daniel Terdiman visited Lego to see how the company makes its world-famous bricks.
Daniel Terdiman/CNET

BILLUND, Denmark--There are a lot of different Lego sets. There are pirate sets, Star Wars sets, city sets, space sets, and many more. But at the heart of it all, at the heart of a toy empire with many millions of passionate fans throughout the world, is the brick.

A single Lego brick is nothing special. But put two together and you can start to make things. Add another, and another, and the number of things you can make starts to go up exponentially. Let's say you had six standard four-by-two red bricks. With those pieces alone, there are more than 915 million possible ways they can be arranged. Throw in a few dozen more pieces, and you've really got something.

Yet no matter how many bricks you've got, no matter what set you're working with, your pieces will all fit together. And they'll fit with every other Lego fan's bricks, too. And all of them, all those billions of bricks that Lego has made over the years, have emerged with just about no fanfare at all from what looks like a small engine block: the mold--the core of the entire Lego system.

There are currently more than 7,000 different Lego "elements," as the different bricks are sometimes called, in use in the many different sets the company makes. Each requires its own mold. And each mold is an extremely pricey little device. Indeed, said Roar Trangbaek, Lego's corporate communications manager, these heavy metal contraptions are worth an average of $72,000 apiece. The most expensive weighs in at $360,000. The molds are more expensive than the industrial pressing machines into which they're placed.

And while that may seem like an extravagant amount of value for a chunk of metal that can be used to make only one thing, and a very small, light, plastic thing at that, try taking your kid's Lego bricks away and gauge the reaction. Now try that on a global scale. Maybe $72,000 isn't such a hefty number after all.

Making the world's favorite toy As part of my CNET Road Trip 2011 project, I've come to this rather bland town in western Denmark for a rare opportunity: to see how Lego produces what has to be the world's favorite toy brand. That's not an honor Lego bestows on itself, but I can't imagine any other that competes for that title.

Walking down the street near the company's low-slung headquarters for the first time, there's little question when you've arrived: it's the building with the giant red, yellow, and blue Lego bricks in front.

The truth of the matter is that making a Lego brick is about as simple a manufacturing process as can be. You inject some hot plastic into the mold, press down for a couple seconds, and then release. Out pop the pieces, which then fall onto a small belt, where they then emerge from the production machine and drop into a bin. And that's the end of the story.

Of course, it isn't really. For any real Lego fan, getting to see up close how the bricks are made and turned into real packaged sets, this is a real treat. And the story certainly isn't over once it comes out of the mold. After all, that shiny new brick has to make its way to your house, where it will instantly get lost in the shag of your carpet. And that brief story barely accounts for the complex details that led to that small brick being made.

It all begins, then, with huge silos full of what is called ABS plastic. Shipped by suppliers to Lego's production facilities here, as well as in Mexico, Hungary, and the Czech Republic, it enters the factory mainly in white or red. It's then pumped up into the ceiling in one of several colored pipes and then brought into the molding rooms.

Before the plastic is injected into the molds, it is first mixed with any additional color needed for the individual brick and then heated at the pressing machine to at least 280 degrees Celsius.

Each of the Billund factory's 12 molding facilities--known as modules--has up to 64 pressing machines, split into two aisles of 32. At each machine, the now-heated plastic is pumped into the mold through a main channel. It is then rerouted into a number of much narrower channels, each of which corresponds to one single brick. A mold can produce as many as 32 bricks--or as few as four--at once. As the machine presses the hot plastic, cold water is pumped in to cool the whole thing down, and then after a couple of seconds, the mold opens up and the bricks snap off and fall.

If you look at any individual Lego brick, somewhere on it you'll find a little dot that seems out of place. This is likely the spot at which the brick had its plastic injected through the mold. When the plastic cools, and the mold splits apart, the brick simply breaks off, leaving this little dot. Go ahead: take a look at a brick or two.

Purple Lego bricks emerge from the press machine in one of the molding rooms at the company's Billund, Denmark, production facility.
Daniel Terdiman/CNET

The process in the molding room is almost over, but not quite yet. As each bin fills, sensors alert the system, and before long, a robot trolley trundles over, picks up the bin, and carries it away. Like most of the production, as well as processing and packaging, it's almost entirely automated. Very few people are required for this process.

Processing After the molding process, the bricks move on to a warehouse. Eventually, when they're needed for whatever set they'll be part of, they're pulled out and brought into a processing facility in a different building in Billund.

As Trangbaek points out, one of the efficiencies built into the Lego system is that many different elements can be used in a wide variety of sets. In addition, many can eventually be configured different ways. For example, there are some small blue round elements that may be used as the heads on mini-figures (the little Lego people) or as decoratives for other purposes.

During processing, the various bricks and elements in their entirely plain forms are taken through a new kind of machine that adds any necessary printing or embellishments. The ones I saw were processing various mini-figures that arrived as bare torsos and gradually had robots snap on arms and legs, and heads, and then print on various faces and outfits.

Again, this is a fairly simple system, with just a few steps, but watching it in action is exciting--it is, after all, getting to see something you and everyone else played with come to life, as it were.

Piece by piece, the mini-figures run their way through the machines, getting grabbed and turned around, becoming ever more like the little Lego people that countless kids will eventually play with. And then they emerge from the machines, and are gone.

Packaging Next it's on to packaging. While I was there, I got to see the various bricks and elements of a Star Wars set--specifically a General Grievous Starfighter, set number 8095--get put together.

First, a black box travels along a line, collecting various pieces for the set. The box then heads up a belt and empties the pieces into a machine, where they are then dropped into a second black box. That new box moves along, has a few more pieces drop in, and then it moves into a bag-making machine, drops its pieces, and the machine makes what is known as a prepack bag.

Because, Trangbaek points out, the worst thing that can happen is that someone opens a set only to find a crucial piece missing, Lego sometimes adds a second piece, especially if it is light and won't upset the weight tolerances the automatic system accepts. That system is designed to ensure that only the right number of pieces go in a set, and that is usually determined by total weight.

Now, the prepack bags move along a belt, where they are joined by others. And then they encounter the boxing machine. First, the actual product boxes are automatically put together by one machine, and then the packs are dropped in. A device pushes down on the packs inside the box to make sure they don't come up too high to allow the box to be closed. And then, finally, the boxes are sealed shut, automatically weighed to make sure they're correct, checked as they pass by on the belt by a worker trained to look for things like plastic bags sticking out of the box, and then they're packed by a robot six to a case, and sent off for distribution.

It's a rather sudden end to a fairly romantic process, but it's exciting to know that after the box makes its way to Lego's Czech distribution center, it will soon end up in some kid's hands. Or maybe an adult's. You never know.